Backflow Characteristics And Gas Production Technology Of High Pressure Shale Gas Reservoir In Zhaotong Area

Since the shale gas reservoir itself does not contain water,the produced water in the production process is mainly fracturing and returning liquid.Different wells show a certain difference in the characteristics of the backflow.It is necessary to analyze the characteristics of the shale gas well returning,which could provide guidance on the timing of the drainage and gas recovery process and the appropriate gas recovery technology.At the same time,the shale gas adopts the “long horizontal section” development mode,and the domestic development time is still short.The drainage and gas recovery process of the system is not formed yet,and the gas production process technology needs to be researched and optimized.Based on the back-slide characteristics of shale gas pressure,this paper studies the correlation between the return indexes of shale gas wells,reservoir quality,completion quality and other key indicators,and optimizes the gas production process plan according to the return-flow situation.Starting from the seepage and lifting pipe flow of shale gas reservoirs,the node analysis is carried out,aiming to reasonably match the production parameters according to the actual production capacity of the gas wells and achieve overall optimization.The adaptability and accuracy of various wellhead effusion pre-judging methods such as production curve method,oil sleeve pressure difference method and critical liquid-carrying flow method in the development and lifting of shale gas horizontal wells are analyzed.Focusing on the two critical liquid-carrying flow models of Turner and Li Wei and the actual production data,the model was modified.The results show that the modified model can meet the shale gas well pre-judgment in the demonstration area to determine the drainage and gas production.The timing of the process implementation provides theoretical guidance.Combined with the development method and backflow characteristics of shale gas wells,a combination evaluation method based on analytic hierarchy process and geometric mean is used to evaluate the different ways of drainage and gas lift,and the gas production process is preferred.Focus on the high-rated preferred column,foam drainage gas,plunger lifting process to carry out supporting technology research,and evaluate the field application effect.The results show that the better the reservoir quality and completion quality,the lower the return rate,the more complicated the fracture system,the lower the return rate,and the higher the mineralization degree of the return fluid,which can be used to predict the return characteristics of the new well.Using the Li Wei-Turner model with a coefficient of 0.1 to calculate the critical liquid carrying flow,and the high coincidence rate with the site could be used as the basis for determining the reasonable timing of the drainage and gas recovery process,comprehensive evaluation of different lifting methods to determine the ranking of the scale.The preferred column technology and four foam drainage technologies have been formed,and the design parameters of the plunger lifting process parameters and the diagnostic methods for operating conditions have been developed.